ElectricPavlov

'those'   are typically  NOT 'THESE'            are you trying to learn English on a MATH FORUM????

Say she scored  50 % on the first two exams    that would   50   and 50

she scored 13% lower on the next 5            that would be    37  and 37  and 37 and 37 and 37

Add all of her scores and divide by the number of scores to find her NEW average

(50+50 + 37 + 37 + 37 +37 + 37 ) / 7    = 40.71      

She HAD a 50% average, now it has gone DOWN  to 40.71 %    Down  9.28% points.

Just pick ANY two numbers for 'x' and see what 'y' equals for those x's

let's pick    x= 2      and x= 3

for x= 2    4(2) - 6y=0

8-6y=0

8=6y

8/6 = 1 1/3 = y      so our first ordered pair is   (x,y) =  ( 2, 1 1/3 )

For x = 3

4(3) - 6y = 0

12 = 6y

12/6 = 2 = y       so our second ordered pair (x,y)    would be    (3,2)

Just USE the calculator !   9 x pi = 28.27433388.......

Remember, when dealing with exponents      (a^b)^c   =  a ^(b*c)

(5^(1/5))^5  = 5^(1/5  * 5)   = 5^1 = 5

You'll need to look at a periodic table to get all of the molecular weights

Mg=24.305                =24.305

N =14.007           x 2  =28.014                     (there are TWO N's in each molecule)

O=15.999            x 6  =  95.994                  (there are SIX O's in each molecule)

Total =                         =148.313

The FRACTION of this total that is Oxygen   is  95.994/148.313   of the total

99.994/148.313  x 860  = 556.63 grams of oxygen

2/3  /    1/2        when DIVIDING fractions, flip the BOTTOM one over and MULTIPLY

2/3   x   2/1   =  (2x2) / (3 x1)  =  4/3  =  1 1/3

-2 = 2(x-3)    First expand the right side

-2 = 2x - 6      Add 6 to both sides

4 = 2x             divide by 2

2=x

F=ma    First of all.

If 20 N are applied to the block   5 N are 'used' to overcome friction for a 'net' force of 15N applied to the block

15 N = 10 kg  x  a

15 kg m/sec^2 = 10 kg x a

15/10 = a    =  1 1/3  m/sec^2

Games won so far     .65 x 40 = 26 games won so far   they need to have 35 wins   so 9 more games out of TEN remaining

9/10 = 90% <------  they must win 90% of the remaining (10) games to qualify